Modafinil improves information processing speed and increases energetic resources for orientation of attention in narcoleptics: double-blind, placebo-controlled ERP studies with low-resolution brain electromagnetic tomography (LORETA).

Author(s): Saletu M, Anderer P, Saletu-Zyhlarz GM, Mandl M, Saletu B, Zeitlhofer J

Affiliation(s): Department of Neurology, Medical University of Vienna, Wahringer Gurtel 18-20, Vienna, Austria. michael.saletu@chello.at

Publication date & source: 2009-09, Sleep Med., 10(8):850-8. Epub 2009 Apr 1.

Publication type: Randomized Controlled Trial; Research Support, Non-U.S. Gov't

BACKGROUND AND PURPOSE: Recent neuroimaging studies in narcolepsy discovered significant gray matter loss in the right prefrontal and frontomesial cortex, a critical region for executive processing. In the present study, event-related potential (ERP) low-resolution brain electromagnetic tomography (LORETA) was used to investigate cognition before and after modafinil as compared with placebo. PATIENTS AND METHODS: In a double-blind, placebo-controlled cross-over design, 15 patients were treated with a 3-week fixed titration scheme of modafinil and placebo. The Epworth Sleepiness Scale (ESS), Maintenance of Wakefulness Test (MWT) and auditory ERPs (odd-ball paradigm) were obtained before and after the 3 weeks of therapy. Latencies, amplitudes and LORETA sources were determined for standard (N1 and P2) and target (N2 and P300) ERP components. RESULTS: The ESS score improved significantly from 15.4 (+/- 4.0) under placebo to 10.2 (+/- 4.1) under 400mg modafinil (p=0.004). In the MWT, latency to sleep increased nonsignificantly after modafinil treatment (11.9+/-6.9 versus 13.3+/-7.1 min). In the ERP, N2 and P300 latencies were shortened significantly. While ERP amplitudes showed only minor changes, LORETA revealed increased source strengths: for N1 in the left auditory cortex and for P300 in the medial and right dorsolateral prefrontal cortex. CONCLUSION: LORETA revealed that modafinil improved information processing speed and increased energetic resources in prefrontal cortical regions, which is in agreement with other neuroimaging studies.